Events & Seminars

2021 Jan 20

Logic Seminar - Eran Alouf

11:30am to 1:15pm

Location: 

https://huji.zoom.us/j/82821066522?pwd=aVJnTkxBYktycHdzNFN5WDV0R2FkZz09
Dp-minimal expansions of (Z,+)

Abstract:
I will review the research about dp-minimal expansions of (Z,+), and then present a recent result classifying (Z,+,<) as the unique dp-minimal expansion of (Z,+) defining an infinite subset of N.
All the relevant notions will be defined in the talk.
2021 Jan 19

Dynamics seminar: Barak Weiss (TAU). Ergodicity of rel foliations on the space of holomorphic one forms

2:00pm to 3:00pm


Abstract: The rel foliation is a foliation of the moduli space of abelian differentials obtained by "moving the zeroes of the one form while keeping all absolute periods fixed". It has been studied in complex analysis and dynamics under different names (isoperiodic foliation, Schiffer variation, kernel foliation). Until recent years the question of its ergodicity was wide open. Recently partial results were obtained by Calsamiglia-Deroin-Francaviglia and by Hamenstadt. In our work we completely resolve the ergodicity question.
2021 Jan 13

Set Theory seminar - Juris Stperans (York) Universal functions, strong colourings and ideas from PID

2:00pm to 4:00pm

Juris Stperans will speak about

Universal functions, strong colourings and ideas from PID

A construction of Shelah will be reformulated using the PID to provide alternative models of the failure of CH and the existence of a universal colouring of cardinality. The impact of the range of the colourings will be examined. An application to the theory of strong colourings over partitions will also be given. 

Join Zoom Meeting
2021 Jan 13

Logic Seminar - Krzysztof Krupinski

11:15am to 1:00pm

Location: 

https://huji.zoom.us/j/82821066522?pwd=aVJnTkxBYktycHdzNFN5WDV0R2FkZz09
On generating ideals by additive subgroups of rings and an application to
Bohr compactifications of some matrix groups


Abstract:
I will present several fundamental results about generating ideals in
finitely many steps inside additive groups of rings from my very recent
joint paper with T. Rzepecki. I will also mention an application to
computations of definable and classical Bohr compactifications of the
groups of upper unitriangular and invertible upper triangular matrices
2021 Jan 06

Logic Seminar - Hanan Rabinowitz

11:15am to 1:00pm

Location: 

https://huji.zoom.us/j/82821066522?pwd=aVJnTkxBYktycHdzNFN5WDV0R2FkZz09
Results in Borel chromatic numbers using Infinite games and Borel determinacy


Abstract: (Based on the paper “A determinacy approach to Borel combinatorics” by Andrew Marks) 
A Borel graph on a standard Borel space X is a symmetric irreflexive relation G on X that is Borel as a subset of X×X.

A Borel coloring of a Borel graph G on X is a Borel function c from X to a standard Borel space Y such that if
xGy then c(x)!=c(x)
2021 Jan 04

Mark Shusterman [HUJI-BGU Number Theory Seminar]

4:30pm to 6:00pm

The meeting will be open from 16.15 (local time) *NOTE UNUSUAL TIME* for a virtual coffee with the speaker. 

Title: Short exponential sums and their applications over function fields

Abstract:

In joint work with Will Sawin, we obtain (square-root) cancellation in quite general incomplete exponential sums for the ring F_q[x] of polynomials over a finite field. This has applications to problems in analytic number theory such as the Chowla conjecture, Bateman-Horn conjecture, and the number of real quadratic function fields with a huge class group.

2020 Oct 19

[HUJI-BGU Number Theory Seminar]

Repeats every week every Monday until Fri Jan 15 2021 except Mon Jan 04 2021.
2:30pm to 3:40pm

2:30pm to 3:40pm
2:30pm to 3:40pm
2:30pm to 3:40pm
2:30pm to 3:40pm
2:30pm to 3:40pm
2:30pm to 3:40pm
2:30pm to 3:40pm
2:30pm to 3:40pm
2:30pm to 3:40pm
2:30pm to 3:40pm
2:30pm to 3:40pm

Location: 

https://us02web.zoom.us/j/81568648940?pwd=cVNVa2tpUHM5aDBIaDF6eXpiaHUzZz09
The meeting will be open from 14.15 (local time) for a virtual coffee with the speaker. 

Join Zoom Meeting

https://us02web.zoom.us/j/81568648940?pwd=cVNVa2tpUHM5aDBIaDF6eXpiaHUzZz09

Meeting ID: 815 6864 8940

Passcode: 3628800

2020 Dec 30

Logic Seminar - Daniel Palacin

11:15am to 1:00pm

Location: 

https://huji.zoom.us/j/82821066522?pwd=aVJnTkxBYktycHdzNFN5WDV0R2FkZz09


Solving equations in finite groups and complete amalgamation

Abstract: Roth's theorem on arithmetic progression states that a subset $A$ of the natural numbers of positive upper density contains an arithmetic progression of length 3, that is, the equation $x+z=2y$ has a solution in $A$.
2020 Dec 30

Graduate student seminar

4:00pm to 6:00pm


First Talk: 16:00-17:00

Nachi Re'em: Markov measures  

Abstract: We present measures on product spaces with Markovian type of dependence. We discuss questions like how they should be defined; in what way they are less understood than product measures; and, what nice properties of product measures we may hope to have also in Markov measures. We will assume knowledge in probability in an undergraduate level, as well as general familiarity with the fact that measures on product spaces can be specified on cylinders.

Pages